The invention relates generally to monitoring of components of a subsea well and more specifically to monitoring of pressure/stress in annulus A and annulus B in the subsea well.
In hydrocarbon production, risers, wellheads, and Christmas trees are used as physical interfaces to aid in the flow of hydrocarbons from an oil well to an oil producing asset. To ensure effective collection of hydrocarbons, it is desirable to actively monitor the integrity of a subsea well. The integrity of the subsea well may be compromised due to leakages in production tube, casings or cement work of a well or a wellhead structure, thereby causing pressure to build up in the annulus such as annulus A and annulus B of the subsea well. In certain cases, the tubing of the subsea well may collapse if the pressure difference between different annuli exceeds a threshold value. Therefore, measuring pressure in the annuli and/or the stress in the casing of the subsea wells is crucial for detecting any compromise in the integrity of subsea wells.
Conventionally, pressure sensing in the annulus A of a subsea wellhead is accomplished using traditional pressure sensors. Also, in subsea applications, regulations prohibit any drilling/wiring through a casing wall between the annulus A and B. Accordingly, due to the lack of direct access to the annulus B, measurement of the pressure in the annulus B may be accomplished by disposing a pressure sensor in the annulus B. In addition, disposing the sensor in the annulus B entails providing a communication link and a power supply to the sensor without penetrating the annulus B, in order to avoid a potential leak path in the annulus B. Moreover, these pressure sensors may experience failures due to aging, dirt, moisture, changes in the composition of the ambient fluid, and the like. Replacement of the defective sensors is a challenging task.